Artificial material and process for making same



Patented: Aug. 25,. 1931 PATENT OFFICE I LEON murmur, or vmmu, nus'rumARTIFICIAL MATERIAL AND PROCESS FOR MAKING em Nolli'awing. Applicationfiled. June 3, 1926, serial- No. 113,582, and in Austria June 20, 1925.

Heretofore strong sulphuric acid has not been used as coagulating bathin the manufacture of artificial materials, such as artificial threadsand films from viscose, because, by

; means of. such acid, the formation of a lustrons thread, band, film orthe like has been impossible. (See U. S. Patent 836,452.)

Now I have discovered that this holds good with sulphuric acidcontaining up to about 55. per cent. of H 30 but that sulphuric acidcontaining about 55 per cent. of H SO,, and preferably sulphuric acidcontaining more than 55 per cent.,for example 65 to 86 per cent. of H 80when used as coagulating bath for viscose brought into the form of athread or film or band or the like, yields threads, films, bands or thelike which have a good lustre.

But what is still more important: I have discovered that threads,manufactured from viscose by means of sulphuric acid containing at leastabout 55 per cent. of H 50 preferably however more than 55 per cent. ofH SO for example 70 to 85 per cent. of

H SO with regard to their tensile strength,

surpassany artificial thread known'hitherto and in some cases approach,in some cases equal, and in some cases even surpass even natural fibres,such as cotton or wool or real silk. For example, it ofiers nodifiiculty to produce according to the present process, artificialsilkor staple fibre that has a dry tenacity of more than Qgrammes andeven more-than 3 grammes per denier, for example 3 or even 3,5 to 4grammes perdenier'and in some cases even-more than igrammes per denierand a wet tenacity of 1,5 to 2,5 grammesper denier and more.

A further advantage of the artificial threads manufactured according tothe present processover ordinaryiviscosesilk is their higher resistanceto aqueous alkalis and to soa 4 (lhnsidering that, according to thepresent process, sulphuric acid containing up to 90 and even 95 percent. of H SO gives excellent results, this discovery is extremely sur-5 prising for two reasons: First of all, with a view to the well-knownfact that strong sulphuric acid, for example such containing 60 percent. or more of H have an energetic depolymerizing action on cellulose,just the contrary was to be expected, namely that strong sulphuric acidwould decompose the coagulated thread during or after coa lation andthus render it weak, brittle an litthan any viscose thread knownhitherto.

The second reason why the present invention is surprising is the lustreof the threads,

bands or films, considering that, up to now, it has been believed, thatthe want of lustre in the threads made by means of somewhat strongeracid had been caused by the fact that not enough water had been presentin the coa' lating bath to dissolve the gaseous by-pro acts.

I have further found that it is advantageous to the tensile strength ofthe artificial materials, particularly threads, manufactured accordingto the present process, to stretch the threads either in the coagulatingbath or between the coagulating bath and the collecting device or inboth places.

The process is carried out in such a manner that viscose is brought intothe form of an artificial material and coa lated by means of sulphuricacid, containing at least per cent, of H 50 for example sulphuric acidcontaining 55 to 85 per cent. of monov hydrate; Irrmost cases, forinstance in manufacturing artificial threads or-filaments, or films, orhands, or plates, this can be effected in such a manner that the viscoseis caused to pass through suitably formed openings into sulphuric acid,containing 55 to 98 per cent. of H 50 for instance such of to 85 percent. strength (calculated on H or into a bath containing 55 to 98 percent., for instance 65 to per cent. of monohydrate. The strong sulphuricacid may be employed byitself or in admixture with one or more suitableinorganic substances, for example with another strong mineral acld suchas hydrochloric acid, nitric acid or phosphoric acid, or with a neutralor acid salt, such as sodiumsulphate, sodium bisulphate, ammoniumsulphate, magnesium sulphate, zinc sulphate, sodium bisulphite, sodiumsulphite, sodium nitrite, boric acid or the like. To the strongsulphuric acid or its niixture'with another strong. acid or with one ormore of the inorganic substances mentioned above, there may be added oneor more organic bodies, such as glycerol or a sugar, for ex ampleglucose, or alcohol or a salt of an organic base, for example ofaniline, or an organic acid, such as acetic acid or formic acid orlactic acid or oxalic acid. It a salt is added which is capable ofreacting with the strong sulphuric acid under formation of an acidsulphate, or which mutually interacts with the sulphuric acid, thestrength of the sulphuric acidshould be so chosen that, after the amountrequired for the formation of the acid sulphate or for the mutualinteraction is used up, the coagulating bath contains tree sulphuricacid of the desired strength, but

at any rate not less than 55 parts-by weight of'monohydrate in parts byweight of the precipitating bath.

The strength'of the sulphuric acid depends, ceteris paribus, partly onthe. time of maturing given the alkali cellulose, partly on the time orripening, given the finished viscose and partly on viscosity or amountof cellulose contained in the viscose. which however the invention isnot confined,

it may be stated that viscoses which have ma-,

tured for several days and/or viscoses that have been prepared fromalkali cellulose that has been allowed to mature for a longer time, forexample 2 to 3 days and/or viscoses that are poor incellulose or littleviscous respectively, do not support so strong a sulphuric acid asviscoses that have not been allowed to mature or have been allowed tomature for a 'short time (forinstance 3 to 48 hours), only and/or havebeen prepared frdm alkali cellulose that has been not allowed to matureat all or has been allowed to mature for a shorter time than usual, forexample for 3 to 48 I .hours, and/or are rich incellulose or viscousrespectively. The strength of the sulphuric acid is further, to acertain degree, dependent on'the length of immersion in' the coagulatingbath and the tension given the coagulated ma- As a rule, to

eaaerr.

sulphuric acid or in the bath containing it' may be varied withinwide-limits, for examples from 3 to 60 centimetres and even more, forinstance 1 to 2 meters.

If desired the thread or film or band may be stretched eitherimmediately after its formation, i. e. in the coagulating bathcontaining, or consisting of, strong -sulphuric acid, or subsequently,i. e. between the coagulating bath and the collecting device, such asbobbin or centrifuge, or both in the coagulating bath and between thecoagulating bath and the collecting device. I

The thread or film or band or plate or coated or impregnated materialmay, after Washing, be heated or steamed before or after drying.

Any viscose prepared according to any process or any methodknownhitherto may be used in the present process. The process gives excellentresults with viscoses that are prepared from alkali cellulose that hasbeen allowed to mature for such a time as it is commonly given thealkali cellulose in the artificial silk or film art and also withviscoses in the manufacture of which alkali cellulose is employed whichhas been not allowed to mature at all or has been allowed to mature fora shorter time than such as is usual in the artificial silk or'film art,i. e. not Q5 longer than about 48 hours, for example 1 to 24 hours.

The present process gives excellent results with such viscoses also asare prepared without making alkali. cellulose, .i. e. by direct mixingthe ingredients. 4

If desired, there may beadded to the viscose one or more suitablesubstances known in the viscose-silk art, for example glycerol orglucose or sodium sulphate or sodium sul-' phite or sodium 'bisulphiteor. ammonium sulphate or an alkali silicate Oran-alkali aluminate orammonia.-

The processv eing open-to manifold vari ations', it is not intended toconfine the invention to the following examples given for the practicalcarrying out of the process.

iat

parts by weight of a caustic soda solution of 18 per cent. strength at15 to 18 C., and the mixture allowed to stand for 3 to 24 hours. Thenthe mass is pressed to '300.t o 400 parts by weight, and the residuecomminuted by hand or in a suitable apparatus, for instancein a cooledshredder. The comminuted soda cellulose is then kept for 60 to 72 hoursat room temperature, whereafter 30 to .60 parts by weight of carbonbisulphide are added, and

the reacting mixture, preferably under stirring (for example in a closedkneading inachine) or agitating (for example in a sulphidizing drum),kept for'several (for example 4 to 8) hours at 16 a 20 o. Thereafter theexcess of the carbon bisulphide is removed by driving ofi'orievacuating, and then the su'lphidized mass is dissolved in water ordilute caustic soda solution in such a manner that the viscose containsabout 8 to 12 per. cent.

of cellulose (determined in the known manner by precipitating with'acid,washing and or through both and freed from gas bubbles if any.Immediately after, or after it has been allowed to ripen at 1618 C. fora' shorter (for example 12 hours to two days) or a longer (for examplefour days to seven days) time, the viscose is spun in a known mannerinto oneof the following precipitatingbaths:

( l) Sulphuric acid of 50 to 55 B., or

(2) Sulphuric acid of to B., or

(3) A solution of,13,3 parts by weight of ammonium sulphate in 120 partsby weight of sulphuric acid of 50 to B., to which 7 to 9 parts ofsulphuric acid of 66 B. have been added, or a (4) A solution "of 10 to15 parts by weight of glucose in 190-185 parts by weight of S111- phuricacid of 45 to 55 B.

The temperature of the coagulating bath is kept at 0 to 16 0., forinstance at8 C., or at 4 to s C. 1

The length of immersion in the coagulating bath of the threads formingtherein may be short, for example 10 centimetres or long, for instancefrom 30 to 100 centimetres and more. They are then collectedin a knownmanner on a bobbin or in a spinning centrifuge which may be placedeither'by the precipitating bath or at a distance from20 to 120centimetres from the bath, whereupon the threads are washed anddried.

The threads may bestretched in any known manner whilst they are in thecoagulating bath, or after they have been removed-from the bath, i. e.between the coagulating bath and the collecting device. This maybe donefor example either by choosing a more or less long distance between thebath and the collecting device, or by leading the threads over rods orhooks arranged in the bath or between the bath and the collectingdevice, or in the bath andbetween the bath and the collecting device.The speed of spinning may be varied within'widelimi-ts. As a'rule towhich, however, the invention is not intended to be confined, it may beassumed thatthe upper limit of speed possible Is dependent partly uponthe temperature oi the coagulatingv bath, partly upon the length ofimmersion, partly upon the distance between the coagulating bath and thecollecting device, partly u on the degree of stretching given the threaduring spinning, and partly upon the quantity of viscose delivered bythe pump. The followingexamples to which, however, the process is notintended to be limited, may be adduced for the purpose of illustration.

(1) If. the coagulating bath is used at a temperature below 0 C.,for,example at minus 5 6., and if the length of immersion is 60 to 120,for example 80 centimetres, and if the distance between the coagulatingbath and the collecting device, for example bobbin, is

'60 to 150 centimetres, for instance 120 centimetres, and if thestretching given the thread between the coagulating bath and thecollecting device is comparatively high, and if the pum' delivers about2 to '3 cubic centimetres 0 viscose a minute, then excellent re-.

sults are obtained with a speed'of 18 to 26 meters a minute, or of 30meters a minute, but also a higher speed, for example of 30 to 40 metersa minute may be employed if desired.

(2) If all spining conditions remain the same as in (l) except that thepump delivers 4 to 5 cubic centimetres ofviscose a minute,

then if desired a speed up to 40 to 60 meters a minute may be employed.

(3) If the spinning conditions are exactly -as 1n (1) except that thetemperature ofthe coagulating bath is plus 4 to plus 25 (1.,

for example 8 (3., if desired the speed may be up to 50 to 60 meters aminute.

It in ('1) the length of immersion or the distance between thecoagulating bath and the collecting device or bothare shortened, .it isrecommendable not to use too low a speed.

Before being washed, the threads may be treated in any known mannervwitha coagulating bath known in the viscose-silk art, for

example a solution of sodium bisulphate or sodium bisulphite or withdilute sulphuric acid or the like.

1 The washed threads may, before orafter dr ing, be heated G- orsteamed.

They may also be treatedwith any des'ulphurating' or bleaching agentknown in the viscose art.

(for example at 100110 or (b) with the difierence that thesoda-cellulcse is pressed to 200 parts by weight.

I l (a) to (0) Mode of operation as in Example vI (a) or I (b) or I (0),with the difi'erence (1) that the sulphidized mass is dissolved (b). Themode of operation is as in (a), I

in water or dilute caustlc soda solution so as to yield a viscose thatcontains 5 to 8 per cent. of cellulose, for instance, 6 to 7 per 66 B.have been added, or

(4) A solution of 10 to parts by weight of glucose in 190 to 185 partsby weight ofamples.

sulphuric acid of 55 to 60 B.

III (a) to (0) Mode ofoperation as in Example I (a) or I (b) or I (0) oras in Example II (01) or II (6) or II (0), with the exceptionthat the,

viscose is not allowed to mature at all or to mature for 12 to 48 hoursonly, and that as coagulating bath sulphuric acid of 60 to 64 B., forinstance sulphuric acid of 62 B. at 6 to 10 C. is used.

In using so strong an acid it is preferable to run the spinning at ahigh spee for example to 60 meters a minute.

I V (a) to (e) (a). 100 parts by weight ofsulphite-pulp or linters areimpregnated with 900 to 2000 parts by weight of a caustic soda solutionof 18 per cent. strength at 15 to 18 (1., and the mixture allowed tostand for 3 to 24 hours.

Then the mass is. pressed to 300 parts by" weight, and the residuecomminuted by hand orin a suitable apparatus, .for instance ina cooledshredder. Immediately or soon (for.

example 1 hour) after the comminution has taken place, 30 to 60 parts byweight of carbon bisulphide are added, and the reacting mixture,preferably under stirring (for example in a closed kneading machine) oragitating (for example in a sulphidizing drum), kept for several (forexample 4 to 12) hours vat 16 to 20 C. Thereafter the excess ofthecarbon bisulphide is removed by driving 011' or evacuating, and thesulphidized mass, the' I weight of which generally amounts to from about330 to 400 parts by; weight, is dis-' solved in 650 to 900 parts byweight of a caustic soda solution of 6.5 to 10 per cent. strength. Theviscose solution thus obtained is then filtered in a known mannerthrough cotton wool or a dense cotton fabric or through both and freedfrom gas bubbles if any; Immediately after, or after it has been allowedto ripen at 16-18 C. for a shorter (for example 12 hours to two days) ora longer (for example four days or seven days) time, the viscose is spunin a known manner of glucose in 190-185 parts by weight of sulphidizingo the soda-cellulose.

.used as coagulating bath, the viscose being into one of the followingprecipitating baths (1 Sulphuric acid of 60 B., or (2 Sulphuric acid 06B., or (3) A solution of 13.3 partsby weight of ammonium-sulphate in 120parts by weight of sulphuric acid of 55 to B., to which 9 to 10 parts ofsulphuric acid of 66 B. have been added, or (4) A solution of 10 to 15parts by weight phuric acid of 55 to 60 B. The temperature of thecoagulatlng bath is kept at 0 to 16 0., for instance at 8 C., drat 4t08C.

The spinning and treating of the threads during and after spinning isdone in the same manner as. described. in the foregoing ex- (b).The'mode of operation is as in (a), with the difference that a causticsoda solution of 3 to5 per cent. strength is employed for the,dissolving of the sulphidized soda cellulose. Accordingly, the viscose1s somewhat more viscous. (c) The mode of operation is as in (a.) or (b)except that 75 to 150 parts by welght of carbon bisul hide are employedfor the sul- (d). Themode of operation is as in (a) or (b) or (0), withthe difference that the sodacellulose is pressed to 200 parts by weight.

(e) The mode. of operation is as in (a) or (b) or (c) or (d), with thediflerence that sulphuric acid of 62 to 64 B. at 8 C. is

12 to 48 hours'old and the speed of spinning .100 about 45 to 60 metersa minute. g

V (a) to' (e) The method of preparing the viscose differs from thatdescribed in IV (a) or (b) or (0) or (d) or (e) in that thesoda-cellulose, after pressing and comminuting and before beingsulphidized, isallowed to ripen for 3 to 24 hours at 16 to 20 C. Theamount and concentration of the caustic soda solution used forthedissolving of the sulphidlzed mass-maybe equal to those used in ExampleIV or somewhat lower, for example so as to produce a 10 to 12 per centviscose (calculated on starting cellulose).

The workingup into threads is efi'ected as IV (a) to (e).

VI (a) to (d) (a). -100 partsby weight of finely-'di- -videdsulphite-pulp or bleached cotton are mixed with 920-900 parts by weightof a caustic soda solution of 8 to 10 per cent. strength. To thismixture 40 to 150 parts by weight of carbon bisulphide are added and thereacting mixture kept at room temperature for 12 to 72 hours, preferablyunder continual or temporary stirring or kneading. The viscose solutionthus obtained is then in filtered in a known manner through cotton woolor a dense cotton fabric or through both and freed from as bubbles ifany. Im-.

mediately after, or a ter it has been allowed to ripen at 16-18 G. for ashorter (for example 12 hours to two days) or a longer (for example fourto seven days) time, the viscose is spun .in a known manner into one ofthe following coagulating baths:

1; -Sulphuric acid of 55 to 60 B., or 2 Sulphuric acid of 45m 50 B., or(3) A solution of 13,3 parts by weight of ammonium sulphate in 120 partsby weight of sulphuric acid of 45 to 60 B., to which 7 to 9 parts ofsulphuric acid of 66 Be, have.

been added, or

Patent 212,865, for example according to the following examples of saidspecification: I (a) to (s) or II (a) to (a) or II (a) to c) or IV (a)to (e) or V (a) to, b) or VI a) to (c) or VII or VIII or IX or or XII orXIII. v I v Mode of operation as in (a) or (b), with the exception that,before or after the addition of carbon bisulphide takes lace, a smallquantity of a catalyzer is adde to the mixture of the cellulosic bodywith the caustic alkali solution, for example 0,2 to 1 parts by weightof a soluble chromicsalt or nickel .salt or iron salt; 1

((1) Mode of operation as in (a) or with the diflerence that, before orafter the addition of carbon bisulphide takes place, a small quantity ofa soluble peroxyde, such as 5 to parts by weight of sodium peroxyde to100 parts by'weight of starting celluloseare added. 7 i V! I 100 partsby weight of sulphite-pulp are placed in a cooled shredder admitting ofbemg hermetically'closed, whereu on 200 parts by weight of a causticsoda solutlon of 12 to 20 per cent. strength are added, preferably insmall portions. As soon-as the mass is homogeneous, 40 to parts byweight of carbon bisulphide are added, whereupon the shredder is closed.After 4 to 8 hoursthe reaction mass is removed from the shredder anddissolved in 920 parts by weight of a caustic 'soda solution of 6,15 percent, strength, the weight of the sulphidized mass being 330 parts. Thefinal viscose contains 8 per cent. of starting cellulose.

The filtering and spinning of this viscose and the treatment of'thethreads is doneas in the foregoing examples.

Examples for producing staple fibre follow automatically from theforegoing examples. f

According to the foregoing examples, it is possible to obtain artificialsilk or staple fibre which has a considerably higher dry and wettenacity than silk spun under same spinning conditions, but by means ofchemicals customary in the viscose silk-art, for example by using aknown precipitating bath. For example: it is not difiicult to produceafter the present process artificial silk having a dry tenacity of morethan 2 grammes per denier,

1 even more than 3 grammes per denier, for example 3 grammes to 4grammes per denier and a wet tenacity of 1,5 to 2,5 grammes per denierand more.

' VIII A viscose prepared as described in Example I or II or III or IVor V or VI or VII is caused to pass through a suitable hopper or slit inone of the coagulating liquors mentioned in these examples, and afterhaving left the precipitating bath, is washed and dried in any knownmanner.

A cotton fabric is impregnated or filled or coated once or several times.with a viscose prepared according to one ofthe methods described inExample I or II or III or IV or V or VI .or VII, for which purpose anysuitable machine, such as a padding machine or a back fillin'g'machineor a spreading machine may be emplo ed. To the viscose there may beadded a lling substance, for instance talcum or china clay or acolouring matter or a pigment such. as mica, or soot or a mineral colouror the like; or coated material is, without beingdried,

through one of the precipitating baths described in Example whereuponthe material'is washed and dried. v

' Instead of strong sulphuric acid there may be used in the foregoingexamples a strong halogen hydracid, such as hydrochloric acid,

' for example of 25 to 40 per cent. strength, or

nitric acid, for example such as contains 6.0

from 60 to per cent. of H AsO In the foregoing examples, in thepreparation of viscose, instead of wood pulp, there treated in the coldor in the heat with dilute acids, for example hydrochloric or sulphuricacid, in short any'kind of cellulosic bodies employed in, or proposedfor the manufacture of viscose.

The impregnated 'optionally in the stretched state,- taken 'to'90 percent. of I-INOg, or phosphoric acid,

for example of 1,5 to 1,86 specific gravity, or arsenic acid, forexample such as contains" may be used bleached cotton, or cellulose Theexpression strong sulphuric acid or sulphuric acid containing at least55 per cent. of sulphuric acid monohydrate means in the description andclaims: sulphuric acid of 55 to 98 or 100- per cent. strength.

The expression: artificial material in the description and claims isintended to mean:

artificial threads and filaments of any kind,

. for example artificial silk, staple fibre, artificialcotton,artificial wool, artificial hair, films, plates, coatings and fillingsof any kind.

The expression heating in the claims is intended to cover anyknown kindof heating, steaming included.

The statements in the description and claims regardingpercentages relateto percentages by Weight.

Iclaimr 1. Process for manufacturing artificial materials from vlscose,which comprises bringing a viscose, prepared from an alkali cellulosewhich has been allowed to mature only from naught to 48 hours, into theform of an artificial material and acting upon it with sulphuric acidcontaining at least 55 per cent. of sulphuric acid monohydrate.

2. Process for manufacturing artificial materials from viscose, whichcomprises calls-- ing a viscose, prepared from an alkali cellulose whichhas been allowed to mature only from naught to 48 hours, to pass throughsuitably formed openings into a coagulating bath whlch contains at least55 per cent. of sulphuric acid monohydrate. I

. '3. Process for manufacturing artificial ma-- terials fromviscose,which comprises causing a viscose, prepared from an alkalicellulosewhich has been allowed to mature only from naught to 48 hours,'to pass through suitably formed openings into acoagulating bathcontaining at least 55 per cent. of sulphuric acid monohydrate andkeeping the bath at a temperature below room temperature.

4. The process .for manufacturing artificial stron mineral acid of astrength equivalent to at east 55 per cent sulphuric acid monohydrate.

6. The rocess for manufacturing artificial suitably, formed opening intoa bath which contains a mineral acid present in an amount equivalent toat least 55 per cent. sulphuric acid monohydrate. v 7. The process formanufacturing artificial thread of high dry tenacity which comprisescausing a viscose, prepared from alkali cellulose which has been allowedto mature only from naught to 48 hours, to pass through a suitablyformed opening, thereafter contacting it with a liquid which contains astrong mineral acid present in an amount equivalent to at least percent. sulphuric acid monohydrate and washing the thread.

- 8. The process for manufacturing artificial thread of high drytenacity which comprises causing a viscose, prepared from alkalicellulose which has been allowed to mature only from naught to 48 hours,to pass through a suitably formed opening, thereafter acting upon itwith sulphuric acid containing at least per cent. sulphuricacid'monohydrate and Washing the thread. 5

9. Process for manufacturing artificial materials from viscose, whichcomprises bringing a viscose, prepared from an alkali cellulose whichhas been allowed to mature only from naught to 48 hours, into tlge formof an artificial material and acting upon it with a bath which" has acoagulating action on said viscose and a plasticizing action on thecoagulated product.

10. Process for manufacturing artificia materials from viscose, whichcomprises causing a viscose, prepared from an alkali cellulose which hasbeen allowed to mature only from naught to 48 hours, to pass throughsuitably formed openings into a bath of concentrated acid coagulatingagent which bath has a plastici'zing action thereupon.

In testimon whereof I aflix m sigjnature.

R. LEON LILIE F LD.

threads 0 high dry tenacity which comprises causing a viscose, preparedfrom alkali cellulose which has been allowed to mature only fromnaughtto 48 hours, to pass through a

